Data on the angular characteristics of the spiral structure of the narwhal tusk.

We studied morphometric features of the spiral structure of the narwhal tusk and show that angular parameters of the arcs of the cementum layer determine the pattern of the spiral structure of the tusk. Given the straight shape of the tusk and the inclined pattern of the arcs of the cementum layer, the angular characteristics of the spiral were determined through the ratio of the legs of a right triangle, which was a basis for calculating the tangent of the angle of inclination. We found the angle of inclination through the arctangent.

Papillomatous Skin Netting of Cetaceans (Cetacea: Delphinapterus leucas, Balaena mysticetus, and Eschrichtius robustus) and Sirens (Sirenia: Trichechus manatus and Dugong dugon).

The structure of the papillomatous junction between epidermis and dermis (papillomatous netting, PN) in the skin of cetaceans (white whales, bowhead, and gray whales) and sirens (American manatee, dugong) was studied and compared using histophysiological and morphogeometric methods. The relative extent of PN development proved to be similar in members of both orders, but significant differences were found in PN configuration, the volume of "free area of grille", the degree of skin vertical compression, and skin density, which influence buoyancy. The differences are discussed from the viewpoint of species biology.

Summer molting of bowhead whales Balaena mysticetus Linnaeus, 1758, of the Okhotsk Sea population.

In bowhead whales summering in Ulbanskiy Bay of the Okhotsk Sea, molting of epidermis has been found and histologically confirmed. The outer layer of the molting whale epidermis is longitudinally stratified and rejected in the form of relatively large plates up to several millimeters thick, each representing a lamellar formation consisting of longitudinal rows of parakeratocytes with degenerated nuclei, numerous pigment granules, and lipid inclusions. Molting intensity is correlated with the level of proliferation and regeneration of all epidermal layers, which helps to maintain the optimal skin thickness.

[Structural organization of anterior corneal epithelium of the African ostrich eye].

This investigation was aimed at the histological study of anterior corneal epithelium (ACE) of adult male ostrich Struthio camelus Linnaeus, 1758 (Struthioniformes). The total thickness of ACE was equal to 48.5+/-1.

[Analysis of the histoenzymatic activity in the sebaceous glands of the Kopetdag pine vole].

This work presents the results of the semi-quantitative evaluation of histochemical phosphatase activity in the sebaceous glands of the Kopetdag pine vole (Microtus socialis paradoxus Ognev et Heptner, 1928). The studies included the conversion of standard histochemical designations of enzymatic activity into digital analogues, allowing to evaluate the level of enzymatic activity and sexual dimorphism. In male voles, the index of the acid phosphatase enzymatic activity was 16% higher in summer than in winter.